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Thread: How to caculate focal lenght?

  1. #1

    Default How to caculate focal lenght?

    A40's close up is 26cm, if i use a macro lens [+10], then what will it be?

    I also got +3 close up.........same calculation?

    couldn't get a gd pic~~~ using the +10........most images seems OOF~~~.......may be like .....the er ....who ...just said......is becos of my hands?
    DSLR newbie: 400D + Tamron 18-200mm + 50mm F1.8 (i simply love it!)
    Canon G2

  2. #2
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    Default Re: How to caculate focal lenght?

    Originally posted by digi~ET
    A40's close up is 26cm, if i use a macro lens [+10], then what will it be?

    I also got +3 close up.........same calculation?

    couldn't get a gd pic~~~ using the +10........most images seems OOF~~~.......may be like .....the er ....who ...just said......is becos of my hands?
    ok try to aim with LCD, move back and forth across the subject... if at any point the subject pops into focus u know u're almost there... then stop down your cam, ie turn aperture to something really tiny like f11 and take a shot at the sharp spot... if your hand shakes badly, try a tripod + timer or practice on the table top first...
    but A40 dun have much zoom think maybe you try to movecloser than 26cm..
    "I'm... dreaming... of a wide... angle~
    Just like the ones I used to know~"

  3. #3

    Default Re: Re: How to caculate focal lenght?

    Originally posted by denizenx


    ok try to aim with LCD, move back and forth across the subject... if at any point the subject pops into focus u know u're almost there... then stop down your cam, ie turn aperture to something really tiny like f11 and take a shot at the sharp spot... if your hand shakes badly, try a tripod + timer or practice on the table top first...
    but A40 dun have much zoom think maybe you try to movecloser than 26cm..
    but if shooting insects how to use tripod???
    why use f11??? i tot need to use bigger aperture like 2.8 to get the sharp spot with the background blur. ??
    DSLR newbie: 400D + Tamron 18-200mm + 50mm F1.8 (i simply love it!)
    Canon G2

  4. #4

    Default Re: Re: Re: How to caculate focal lenght?

    Originally posted by digi~ET


    but if shooting insects how to use tripod???
    why use f11??? i tot need to use bigger aperture like 2.8 to get the sharp spot with the background blur. ??
    Using a closeup filter will result in a shallower DOF, so using a small aperture will compensate for it (You will still get blur background though ). Using a +4 closeup, the focus distance is 100 / 4 = ~25 cm and +10 is 100 / 10 = ~10cm. Also with a closeup filter, you need not use the macro mode of your cam. Just zoom in all the way Hope this info helps

  5. #5

    Default Re: Re: Re: Re: How to caculate focal lenght?

    Originally posted by Newbie123


    Using a closeup filter will result in a shallower DOF, so using a small aperture will compensate for it (You will still get blur background though ). Using a +4 closeup, the focus distance is 100 / 4 = ~25 cm and +10 is 100 / 10 = ~10cm. Also with a closeup filter, you need not use the macro mode of your cam. Just zoom in all the way Hope this info helps
    no matter what camera i use...just take 100/10 ?
    DSLR newbie: 400D + Tamron 18-200mm + 50mm F1.8 (i simply love it!)
    Canon G2

  6. #6

    Default

    Think so cos I see no diff

  7. #7

    Default

    u mean no diff across diff camera or?
    DSLR newbie: 400D + Tamron 18-200mm + 50mm F1.8 (i simply love it!)
    Canon G2

  8. #8
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    Default

    Just Do It.

    no tripod then try with flash..
    "I'm... dreaming... of a wide... angle~
    Just like the ones I used to know~"

  9. #9

    Default

    Originally posted by denizenx
    Just Do It.

    no tripod then try with flash..
    sure^^|
    DSLR newbie: 400D + Tamron 18-200mm + 50mm F1.8 (i simply love it!)
    Canon G2

  10. #10
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    Default

    y not go here to see more.....its azone's homepage to be exact....

    I think he included some calculations which u'll be interested to know.........

    hope its useful to u

  11. #11

    Default

    Originally posted by Revo
    y not go here to see more.....its azone's homepage to be exact....

    I think he included some calculations which u'll be interested to know.........

    hope its useful to u
    thankx^^ it helps alot^^ time for trial^_^
    DSLR newbie: 400D + Tamron 18-200mm + 50mm F1.8 (i simply love it!)
    Canon G2

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